1. Field of the Invention
The invention relates generally to regulated alternating current power supplies and, more particularly, to applications where the load is sensitive to AC field interactive effects.
2. Description of the Prior Art
In the prior art, the regulation of alternating current supplies has been accomplished in a number of ways. Where regulator response time requirements were not particularly stringent, electromechanical devices were widely used. Typical of such electromechanical devices is the motor-driven variable ratio transformer or autotransformer. Other approaches included the so-called saturable reactor regulator and other species generally characterized as magnetic amplifier regulators.
The advent of power-handling solid state devices such as Thyristors and power transistors has made possible the regulation of alternating current sources by means of controllable series elements, such regulators resembling more closely the familiar series regulators extensively used for the regulation of DC power in vacuum tube equipment.
Still other devices employing such expedients as nonlinear resistors, compression-controlled carbon piles, and many others, are also extant in the prior art, viewed broadly.
A particular problem exists in the heater (filament) power supply for pulsed microwave power tubes, such as amplitrons, magnetrons and the now familiar traveling wave tube. In radar systems known in the prior art, traveling wave tube heaters (filaments) have frequently been operated on DC in order to avoid or greatly reduce the problem of magnetic field interaction around the heater as it affects tube operating parameters. Such DC supplies are relatively large, heavy and complex equipments, especially if the residual AC ripple is to be carefully filtered.
The manner in which the present invention overcomes the disadvantages of the prior art in applications of the character described, will be fully described as this description proceeds, and additional advantages will also be evident therefrom.